Data centers are facilities for housing electronic equipment, such as servers. A data center can occupy one room of a building, one or more floors, or an entire building. These facilities often have a large footprint due to the various components necessary for maintaining the facilities, including cooling equipment. Most of the equipment is often in the form of servers mounted in 19 inch rack cabinets, which are typically placed in single rows forming corridors between them. This allows people access to the front and rear of each cabinet. Servers differ greatly in size from 1 U servers to large freestanding storage silos which occupy many tiles on the floor. Some electronic equipment, such as mainframe computers and storage devices, are often as big as the racks themselves, and are placed alongside them. Local building codes can affect the footprint of the facility and thus the overall cost of maintaining the electronic equipment.
Cooling of server racks and cabinets in the facilities can be problematic, particularly as processors typically produce large amounts of heat. It has been found that for every 1 watt of power used for Information Technology, 0.5 to 2 watts of power are used for cooling the electronic components, and thus the need for cooling uses a very high percentage of the total IT power consumption.
The power dissipation of high-performance CPU processors is predicted to exceed 150 W in the near future. The high-density packing of servers and the desire for lower CPU junction temperatures to achieve higher reliability of components means that thermal management of server racks is an increasing concern. Various solutions have been proposed, many of which involve large numbers of fans to keep a constant airflow over the electronic components. However, such solutions suffer from drawbacks associated with the power supply needed to power the fans, as well as reliability of such fans. Moreover, these are generally located in large facilities which further exacerbates the drawbacks.
In a number of solutions, server cabinets are placed on a false floor with cool air from an HVAC system being supplied through the false floor to a vent in front of the cabinet. The cooling airflow is then drawn front-to-back through the cabinet using fans, and vented out to the back of the cabinet. With such arrangements, it is desirable to use a “hot-aisle/cold-aisle” arrangement so that server fronts are arranged facing one another so that two aisles can draw cool air from a single vent area, and so that the server backs also face one another. The hot air is then allowed to vent to air return units in the ceiling. This can lead to “hot spots” in the server room; however, much of the hot air can also mix with the cool air circulating in the room. Various solutions to such problems involve the use of baffles extending from the top of the server cabinet to the ceiling to try to prevent some of the mixing between the hot and cold air.
The maximum allowed temperature range for a server in a data center is typically 59 to 90 degrees Fahrenheit, while the recommended temperature is typically between 68 and 77 degrees Fahrenheit. As the known data center storage solutions typically allow some mixing of air prior to the air reaching the electronic components, data centers typically pump cold air at between 55 and 60 degrees Fahrenheit to account for the temperature increase in the air before it can act to cool the components.